Content clustering is widely known as a grouping technique in which, for example, photographs are grouped based on whether their image capturing positions or image capturing times are close to each other. The amount of content held by a user has increased dramatically along with an increase in capacity of a storage device, and the like. In order to easily search or view a large amount of content, technology has been developed that allows automatic content clustering.
For example, Patent Literature 1 discloses a technology in which clustering of image content items is automatically performed based on the image capturing position, and the generated clusters are further grouped using the image capturing date and time. Patent Literature 2 discloses a technology in which clustering of image content items is automatically performed based on the image capturing date and time.